The report claims police have spoken to "numerous" alleged victims as part of their year-long investigation.

It is understood that Sano's investigation of Pell has been ongoing for the past 12 to 18 months. It is not known whether it is an active or open investigation based on preliminary inquiries.

Cardinal Pell photographed in 2013.

Photo: Joe Armao

Advertisement

Victoria Police declined to comment on the report.

In a statement released by the Catholic Archdiocese of Sydney, Cardinal Pell said the allegations are "without foundation and utterly false" and called for a public inquiry into the leak.

Cardinal Pell, 74, is due to testify to the royal commission on February 29.

He will give evidence via video link from Rome, where he now manages the Vatican's finances, after the royal commission accepted that he was too ill to return to Australia.

Cardinal Pell has previously appeared before the royal commission twice: in person in Sydney in March 2014, and via video link in August 2014, while it was investigating the Church's Melbourne Response, established by the Cardinal while he was Archbishop of Melbourne in 1996.

Cardinal Pell said in his statement that he had been exonerated after claims of historic sexual abuse were made against him in 2002. He said those "false claims" had been ignored by police for 15 years.

The complaint he refers to centres on allegations he abused a boy at a church holiday camp at Smiths Beach, Phillip Island, in the 1960s.

According to the complaint, Cardinal Pell, then a student priest, fondled the young boy's genitals. Cardinal Pell, who always denied the allegations, temporarily stood down as Archbishop of Sydney in 2002 after the accusation was made.

Reports at the time said an investigation by retired Victorian Supreme Court judge Alec Southwell found the accusation could not be established.

The closed-door inquiry – organised via the National Committee for Professional Standards, which also oversees the abuse complaints processes for the Catholic Church, Towards Healing – concluded that both the complainant and the Cardinal were honest witnesses.

"I accept as correct the submission of (counsel) that the complainant, when giving evidence of molesting, gave the impression that he was speaking honestly from an actual recollection. However, the respondent, also, gave me the impression that he was speaking the truth," Mr Southwell said.

The absence of forensic evidence due to the 40-year interval since the alleged offence, the complainant's credibility, lack of corroborative evidence and Cardinal Pell's sworn denial of the accusations were key factors in the inquiry's conclusion, Mr Southwell said at the time.

In December 2015, Sano taskforce detectives investigating historic allegations of abuse publicly appealed for information about sexual assaults at St Patrick's Cathedral between 1996 and 2001, during which time Cardinal Pell was archbishop of Melbourne.

The investigation centres on claims that 14-year-old boys were sexually assaulted at the church.

Detectives were understood to have executed search warrants on buildings linked to the church in East Melbourne, Melbourne, Maidstone and Toorak, on December 2

In his statement on Friday, Cardinal Pell said it was "outrageous" that the sex abuse allegations had been brought to his attention through the media.

"These undetailed allegations have not been raised with the Cardinal by the police", the statement said.

"He strongly denies any wrongdoing. If the police wish to question him he will co-operate, as he has with each and every public inquiry."

"For elements of the police to publicly attack a witness in the same case study that has exposed serious police inaction and wrongdoing is outrageous and should be seen for what it is," the statement said.

"The Cardinal calls on the Premier and the Police Minister to immediately investigate the leaking of these baseless allegations."

A Victorian government spokeswoman said: "If, as reported, there is an investigation currently before Victoria Police it would be inappropriate to comment."

Victoria Police would not comment on the Herald Sun's report.

"Taskforce SANO is currently conducting a large number of investigations into historic sexual offending," Sergeant Anthoula Moutis said.

"Victoria Police will not provide a running commentary on these investigations as it would be inappropriate to do so. Victoria Police encourages all victims of sexual assault and child abuse, and anyone who has knowledge of such a crime, to make a report."

Cardinal Pell is due to give evidence to the Royal Commission in just over one week.

The timing of these leaks is clearly designed to do maximum damage to the Cardinal and the Catholic Church and undermines the work of the Royal Commission.

The allegations are without foundation and utterly false.

It is outrageous that these allegations have been brought to the Cardinal's attention through a media leak. These undetailed allegations have not been raised with the Cardinal by the police and the false claims investigated by Justice Southwell have been ignored by the police for over 15 years, despite the very transparent way they were dealt with by the Cardinal and the Catholic Church.

The Cardinal has called for a public inquiry into the leaking of these spurious claims by elements in the Victorian Police in a manner clearly designed to embarrass the Cardinal, in a case study where the historical failures of the Victorian Police have been the subject of substantial evidence. These types of unfair attacks diminish the work of those good officers of the police who are diligently working to bring justice to victims. The Phillip Island allegations have been on the public record for nearly 15 years. The Southwell Report which exonerated Cardinal Pell has been in the public domain since 2002.

The Victorian police have taken no steps in all of that time to pursue the false allegations made, however the Cardinal certainly has no objection to them reviewing the materials that led Justice Southwell to exonerate him. The Cardinal is certain that the police will quickly reach the conclusion that the allegations are false.

The Victorian Police have never sought to interview him in relation to any allegations of child sexual abuse and apart from the false allegations investigated by Justice Southwell, the Cardinal knows of no claims or incidents which relate to him.

He strongly denies any wrongdoing. If the police wish to question him he will co-operate, as he has with each and every public inquiry.

In the meantime, the Cardinal understands that several media outlets have received confidential information leaked by someone within the Victorian Police.

For elements of the police to publicly attack a witness in the same case study that has exposed serious police inaction and wrongdoing is outrageous and should be seen for what it is.

Given the serious nature of this conduct, the Cardinal has called for a public inquiry to be conducted in relation to the actions of those elements of the Victorian Police who are undermining the Royal Commission's work.

The Cardinal calls on the Premier and the Police Minister to immediately investigate the leaking of these baseless allegations.